1. Field of the Invention
The present invention relates to a recording apparatus and method, and more particularly, to a recording apparatus for and method of improving overwrite characteristics when a mark is recorded on a rewritable medium.
2. Description of the Related Art
Rewritable recording media include write-once recording media, such as CD-Rs, DVD-Rs, and rewritable recording media, such as CD-RWs, DVD-RWs, DVD+RWs, and DVD-RAMs. Rewriting is performed on rewritable recording media, such as phase-change recording media, according to a method of overwriting a new phase-change mark in an area in which a phase-change mark is already written.
FIG. 1 illustrates a jitter characteristic measured based on the number of times overwriting is performed on a CD-RW optical disc for a speed factor of 10 (10×) at speed factors of 4 and 10 (4× and 10×). In FIG. 1, the horizontal axis denotes the number of times overwriting is performed, and the vertical axis denotes the jitter characteristic with respect to overwriting. FIG. 1 shows the result of the measurement of jitter of the phase-change mark according to the number of times overwriting at the speed of a speed factor 1, and when a pulse width of 1T is 220 nsec at the speed factor of 1. Jitter refers to a deviation in a pulse width corresponding to the length of a recording mark with respect to a standard pulse width. Thus, as shown in FIG. 1, jitter can be expressed in nsec.
As seen in FIG. 1, when overwriting is performed on a CD-RW optical disc at a speed factor of 10×, the jitter occurring when writing is performed twice increases by 19 nsec as compared with jitter occurring when writing is performed once. The increase in the jitter occurs because an already recorded phase-change mark is not completely removed. The increase in jitter is a factor due to which data cannot be reproduced.